U.S. patent application number 14/944868 was filed with the patent office on 2016-03-10 for tissue removal device with adjustable sleeve for neurosurgical and spinal surgery applications.
The applicant listed for this patent is Nico Corporation. Invention is credited to Brian C. Dougherty, Joseph L. Mark.
Application Number | 20160066944 14/944868 |
Document ID | / |
Family ID | 41800823 |
Filed Date | 2016-03-10 |
United States Patent
Application |
20160066944 |
Kind Code |
A1 |
Mark; Joseph L. ; et
al. |
March 10, 2016 |
TISSUE REMOVAL DEVICE WITH ADJUSTABLE SLEEVE FOR NEUROSURGICAL AND
SPINAL SURGERY APPLICATIONS
Abstract
A tissue cutting device that is especially suited for
neurosurgical applications is disclosed and described. The device
includes a handpiece and an outer cannula in which a reciprocating
inner cannula is disposed. The inner cannula includes a hinge
between a body section and a cutting section that allows the
cutting section to pivot when the inner cannula reciprocates within
the outer cannula. A tissue collector is also provided and is in
fluid communication with the lumen of the inner cannula. A fluid
supply sleeve is disposed about the outer cannula and is
selectively positionable along the length of the outer cannula.
Inventors: |
Mark; Joseph L.;
(Indianapolis, IN) ; Dougherty; Brian C.; (Terre
Haute, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nico Corporation |
Indianapolis |
IN |
US |
|
|
Family ID: |
41800823 |
Appl. No.: |
14/944868 |
Filed: |
November 18, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12475258 |
May 29, 2009 |
9216031 |
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14944868 |
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12435724 |
May 5, 2009 |
8460327 |
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12475258 |
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|
12404407 |
Mar 16, 2009 |
8496599 |
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12435724 |
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12391579 |
Feb 24, 2009 |
8702738 |
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12404407 |
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12389447 |
Feb 20, 2009 |
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12391579 |
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12336054 |
Dec 16, 2008 |
8430825 |
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12389447 |
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12336086 |
Dec 16, 2008 |
8657841 |
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12336054 |
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Current U.S.
Class: |
606/171 |
Current CPC
Class: |
A61B 10/0283 20130101;
A61B 2017/320032 20130101; A61B 17/32002 20130101; A61B 2017/00977
20130101; A61B 2017/3445 20130101; A61B 17/320758 20130101; A61B
2090/392 20160201; A61B 2217/007 20130101; A61B 17/320783 20130101;
A61B 2017/320052 20130101; A61B 2010/0208 20130101; A61B 10/0275
20130101; A61B 2217/005 20130101; A61B 2017/00017 20130101; A61B
2017/320791 20130101; A61B 17/32053 20130101; A61B 2017/00973
20130101; A61B 2090/3954 20160201; A61B 2017/22079 20130101; A61B
2017/00738 20130101 |
International
Class: |
A61B 17/32 20060101
A61B017/32; A61B 17/3207 20060101 A61B017/3207; A61B 17/3205
20060101 A61B017/3205 |
Claims
1-34. (canceled)
35. A tissue removal system, comprising: a handpiece housing a
motor and being positioned along a first central longitudinal axis
and having a closed distal end; an outer cannula extending from the
closed distal end of the handpiece and having an outer cannula
lumen, a proximal end, a distal end, and an outer cannula opening
adjacent the distal end, wherein the opening defines a cutting edge
for severing tissue; wherein the outer cannula is positioned along
a second longitudinal axis that is axially offset from the first
longitudinal axis such that the outer cannula is not positioned
coaxially with the handpiece; an inner cannula disposed in the
outer cannula lumen and configurable for reciprocating motion
within the outer cannula lumen, the inner cannula having an inner
cannula lumen, a proximal end, an open distal end, and a cutting
edge at the distal end; and an elongated sleeve slidably disposed
about the outer cannula, distal to the closed distal end of the
handpiece, wherein the sleeve comprises an outer cannula channel
and at least one supply channel having an open distal end; wherein
the outer cannula channel is positioned along a first channel axis
that is coaxial with the second longitudinal axis such that the
outer cannula is received within the outer cannula channel, and the
at least one supply channel is positioned adjacent the outer
cannula channel so as not to be coaxial with the first channel
axis, but positioned along a second channel-axis that is parallel
to the first channel axis of the outer cannula channel throughout
an entire length of the supply channel, and wherein the open distal
end of supply channel serves as a delivery conduit to a surgical
site during operation of the tissue removal system.
36. The tissue removal system of claim 35, wherein when the sleeve
is in an uninstalled condition, the at least one supply channel is
separated from the outer cannula channel along the length of the
sleeve.
37. The tissue removal system of claim 35, wherein the sleeve is
selectively positionable along the length of the outer cannula.
38. The tissue removal system of claim 35, wherein the outer
cannula is rotatable with the sleeve and with respect to the
handpiece.
39. The tissue removal system of claim 38, wherein the inner
cannula is rotationally fixed with respect to the outer cannula
such that rotation of the outer cannula causes the inner cannula to
rotate with respect to the handpiece while maintaining a fixed
circumferential relationship between the inner cannula and the
outer cannula.
40. The tissue removal system of claim 35, wherein the sleeve
comprises a imageable material.
41. The tissue removal system of claim 35, wherein at least a
portion of the sleeve is imageable under positron emission
tomography.
42. The tissue removal system of claim 35, wherein the sleeve
comprises a hub at a proximal end of the sleeve, and the outer
cannula projects through the proximal end of the hub.
43. The tissue removal system of claim 35, wherein the outer
cannula is rotatable independently of the sleeve.
44. The tissue removal system of claim 35, further comprising at
least supply channels in the sleeve.
45. The tissue removal system of claim 35, wherein when the sleeve
is in an uninstalled condition, the at least one supply channel is
in fluid communication with the outer cannula channel along the
length of the sleeve.
46. The tissue removal system of claim 35, wherein when the sleeve
is in an uninstalled condition the at least one supply channel is
in communication with the outer cannula channel along the length of
the outer cannula channel, and when the sleeve is in an installed
condition on the outer cannula, the outer cannula separates the at
least one supply channel from the outer cannula channel.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 12/435,724, filed on May 5, 2009, which is a
continuation-in-part of U.S. application Ser. No. 12/404,407, filed
on Mar. 16, 2009, which is a continuation-in-part of U.S.
application Ser. No. 12/391,579, filed on Feb. 24, 2009, which is a
continuation-in-part of U.S. application Ser. No. 12/389,447, filed
on Feb. 20, 2009, which is a continuation-in-part of U.S.
application Ser. No. 12/336,054, filed Dec. 16, 2008 and U.S.
application Ser. No. 12/336,086, filed Dec. 16, 2008, each of which
is hereby incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The present disclosure relates to tissue cutting devices, in
particular, tissue cutting devices that that include a fluid supply
sleeve and which are suited for neurosurgical and spinal surgical
procedures.
BACKGROUND
[0003] Various abnormalities of the neurological system, such as
brain and spinal tumors, cysts, lesions, or neural hematomas, can
cause severe health risks to patients afflicted by them, including
deterioration in motor skills, nausea or vomiting, memory or
communication problems, behavioral changes, headaches, or seizures.
In certain cases, resection of abnormal tissue masses is required.
However, given the complexity and importance of the neurological
system, such neurosurgical procedures are extremely delicate and
must be executed with great precision and care. Some known tissue
cutting systems lack the ability to deliver fluids to or near a
surgical site. Other known systems lack the ability to adjust the
fluid delivery location relative to the tissue cutting location. In
addition, it is sometimes desirable to operate a tissue cutting
device as an aspiration wand. Many systems are unable to operate in
such a mode or are unable to adjust the extent of aspiration. Thus,
a need has arisen for a tissue cutting system that addresses the
foregoing issues.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Embodiments of the present disclosure will now be described
by way of example in greater detail with reference to the attached
figures, in which:
[0005] FIG. 1 is a perspective view of a tissue cutting device
including a fluid supply sleeve in accordance with a first
embodiment;
[0006] FIG. 2 is a cross-sectional view of the tissue cutting
device of FIG. 1 depicting an inner cannula in a first relative
position with respect to an outer cannula in which the inner
cannula's distal end is located proximally of the outer cannula's
distal end;
[0007] FIG. 3 is a cross-sectional view of the tissue cutting
device of FIG. 1 depicting the inner cannula in a second relative
position with respect to the outer cannula in which the inner
cannula's distal end is located at the distal end of the outer
cannula;
[0008] FIG. 4 is a partial cross-sectional view of the tissue
cutting device of FIG. 1 in a first configuration in which a
device-mounted tissue collector is disconnected from a tissue
cutting device housing;
[0009] FIG. 5 is a partial cross-sectional view of the tissue
cutting device of FIG. 4 in a second configuration in which the
device-mounted tissue collector is connected to the tissue cutting
device housing;
[0010] FIG. 6 is a partial cross-sectional view of an alternate
embodiment of the tissue cutting device of FIG. 1 in a first
configuration in which the device-mounted collector is disconnected
from the tissue cutting device;
[0011] FIG. 7 is partial cross-sectional view of the tissue cutting
device of FIG. 6 in a second configuration in which the
device-mounted tissue collector is connected to the tissue cutting
device;
[0012] FIG. 8 is a broken side elevation view of the outer cannula
of the tissue cutting device of FIG. 1;
[0013] FIG. 9 is a broken side elevation view of the inner cannula
of the tissue cutting device of FIG. 1;
[0014] FIG. 10 is a top plan view of a portion of the outer cannula
of the tissue cutting device of FIG. 1 with the inner cannula
removed from the outer cannula;
[0015] FIG. 11 is a top plan view of a portion of the inner cannula
of the tissue cutting device of FIG. 1;
[0016] FIG. 12 is a top plan view of a portion of the outer cannula
and inner cannula of FIG. 1 depicting the inner cannula inserted
into the outer cannula;
[0017] FIG. 13 is a partial cross-sectional view of a distal region
of the outer cannula and the inner cannula of the tissue cutting
device of FIG. 1, depicting the inner cannula in a first relative
position with respect to the outer cannula;
[0018] FIG. 14 is a partial cross-sectional view of a distal region
of the outer cannula and the inner cannula of the tissue cutting
device of FIG. 1, depicting the inner cannula in a second relative
position with respect to the outer cannula;
[0019] FIG. 15 is an exploded assembly view of the tissue cutting
device of FIG. 1;
[0020] FIG. 16a is a side elevation view of a cam of the tissue
cutting device of FIG. 1;
[0021] FIG. 16b is an end elevation view of the cam of FIG.
16a;
[0022] FIG. 17a is a perspective view of a cam transfer mechanism
of the tissue cutting device of FIG. 1;
[0023] FIG. 17b is a perspective view of a cam follower of the
tissue cutting device of FIG. 1;
[0024] FIG. 18 is a partial perspective view of a portion of the
tissue cutting device of FIG. 1 with an upper shell of an outer
sleeve upper housing removed to show a dial for rotating an outer
cannula;
[0025] FIG. 19 is a partial side cross-sectional view of the
portion of the tissue cutting device of FIG. 18;
[0026] FIG. 20 is a side elevation view of an inner and outer
cannula assembly of the tissue cutting device of FIG. 1;
[0027] FIG. 21A is a tissue cutting system including a remote
tissue collector, control console, foot pedal, and the tissue
cutting device of FIG. 1;
[0028] FIG. 21B is an enlarged view of the remote tissue collector
of FIG. 21A;
[0029] FIG. 22 is a block diagram of a control scheme for the
tissue cutting system of FIG. 22;
[0030] FIG. 23 is diagram of the tissue cutting device of FIG. 1
and the motor control unit of FIG. 22;
[0031] FIG. 24 is a partial cross-sectional view of the tissue
cutting device of FIG. 1 depicting motor shaft position sensors for
controlling a stop position of an inner cannula;
[0032] FIG. 25 is a partial cross-sectional view of the outer
cannula and inner cannula of the tissue cutting device of FIG. 1
with the inner cannula in a first position relative to the outer
cannula;
[0033] FIG. 26 is a partial cross-sectional view of the outer
cannula and inner cannula of the tissue cutting device of FIG. 1
with the inner cannula in a second position relative to the outer
cannula;
[0034] FIG. 27 is a partial cross-sectional view of the outer
cannula and the inner cannula of the tissue cutting device of FIG.
1 with the inner cannula in a third position relative to the outer
cannula; and
[0035] FIG. 28 is a side elevational view of the irrigation sleeve
of FIG. 1;
[0036] FIG. 29 is a partial close-up, longitudinal cross-sectional
view of the irrigation sleeve, outer cannula and inner cannula of
FIG. 1;
[0037] FIG. 30 is a transverse cross-sectional view taken along
line 30-30 in FIG. 29;
[0038] FIG. 31 is a close-up, partial side elevational view of the
irrigation sleeve of FIG. 1 selectively disposed along the length
of the outer cannula of FIG. 1; and
[0039] FIG. 32 is a close-up, partial top plan view of the
irrigation sleeve of FIG. 1 selectively disposed over a portion of
the outer cannula opening of FIG. 1.
DETAILED DESCRIPTION
[0040] Referring now to the discussion that follows and also to the
drawings, illustrative approaches to the disclosed systems and
methods are shown in detail. Although the drawings represent some
possible approaches, the drawings are not necessarily to scale and
certain features may be exaggerated, removed, or partially
sectioned to better illustrate and explain the present disclosure.
Further, the descriptions set forth herein are not intended to be
exhaustive or otherwise limit or restrict the claims to the precise
forms and configurations shown in the drawings and disclosed in the
following detailed description.
[0041] Described herein are tissue cutting devices that are suited
for neurosurgical applications such as the removal of spine and
brain tissue. The devices are configured with a fluid supply sleeve
that is disposed on an outer cannula and selectively positionable
along the length of the outer cannula. As a result, the tissue
cutting devices can supply fluids such as irrigants, hemostatic
agents, and tissue sealants to a surgical site. They can also be
used to selectively adjust the area of the outer cannula aperture
through which the aspiration is delivered through to the
tissue.
[0042] Referring to FIG. 1, a tissue cutting device 40 includes a
handpiece 42 and an outer cannula 44. In one exemplary embodiment,
handpiece 42 is generally cylindrical in shape and is preferably
sized and shaped to be grasped with a single hand. Handpiece 42
includes a lower housing 50 which comprises a proximal section 46
and distal section 48. Lower housing 50 comprises a proximal-most
housing portion 82 (FIGS. 2 and 3) that is connected to a motor
housing 71, and a cam housing 69 that is connected to motor housing
71. A front housing section 51 is connected to cam housing 69.
Upper housing 52 is also provided. A tissue collector 58 may be
operatively connected to upper housing 52 (as will be explained in
further detail below). A rotation dial 60 for rotating the outer
cannula 44 with respect to handpiece 42 is also mounted to upper
housing 52.
[0043] As best seen in FIGS. 2, 3, and 20, outer cannula 44
includes an open proximal end 45, a closed distal end 47, and a
distal opening 49 proximate distal end 47. Tissue cutting device 40
further comprises an inner cannula 76 which is partially disposed
in an outer cannula lumen 110 (FIG. 8). Inner cannula 76 is
configured to reciprocate within outer cannula lumen 110 and to cut
tissue samples entering outer cannula 44 via outer cannula distal
opening 49, as will be described in greater detail below. Inner
cannula 76 reciprocates between a proximal position, which is
depicted in FIG. 2 and a distal position which is depicted in FIG.
3. Inner cannula 76 includes an open proximal end 77 and an open
distal end 79. Distal end 79 is preferably configured to cut
tissue, and in preferred embodiments is capable of cutting
neurological system tissues such as those from the brain or spine.
In one exemplary embodiment, inner cannula distal end 79 is beveled
in a radially inward direction to create a sharp circular tip and
facilitate tissue cutting.
[0044] Outer cannula 44 is not translatable, and its position with
respect to handpiece 42 along the direction of the longitudinal
axis of handpiece 42 remains fixed. Fluid supply sleeve 302 (FIG.
1) is selectively attachable to outer cannula 44 and allows fluids
to be provided proximate a surgical site. Fluid supply sleeve 302
has a proximal hub 306 and a distal end 320. An outer cannula
opening 322 is provided at the proximal end of fluid supply sleeve
302. Elongated channel section 304 is connected to proximal hub 306
and projects distally away from it. Distal end 320 of fluid supply
sleeve 302 is the distal end of the elongated channel section 304.
In FIG. 1, fluid supply sleeve 302 is shown in an installed
condition on outer cannula 44. In the depicted installed condition,
fluid supply sleeve 302 is selectively positionable along the
length of outer cannula 44.
[0045] In FIGS. 2-3, fluid supply sleeve 302 is not shown for ease
of viewing. Motor 62 is disposed in proximal lower housing section
46 of handpiece 42 and is operably connected to inner cannula 76 to
drive the reciprocation of inner cannula 76 within outer cannula
lumen 110. Motor 62 may be a reciprocating or rotary motor. In
addition, it may be electric or hydraulic. However, in the
embodiment of FIGS. 2 and 3, motor 62 is a rotary motor, the
rotation of which causes inner cannula 76 to reciprocate within
outer cannula lumen 110.
[0046] Motor 62 is housed in motor housing 71, which defines a
portion of lower housing proximal section 46. Motor 62 is connected
to an inner cannula drive assembly 63 which is used to convert the
rotational motion of motor 62 into the translational motion of
inner cannula 76. At its proximal end, motor housing 71 is
connected to proximal-most housing portion 82, which includes a
power cable port 84 and a hose connector 43, which in the exemplary
embodiment of FIG. 3 is an eyelet. Hose connector 43 provides a
means of securely retaining a vacuum system hose to handpiece 42,
thereby allowing vacuum to be supplied to tissue collector 58.
[0047] Inner cannula driver assembly 63 (not separately shown in
figures) comprises a cam 64, a cam follower 68, a cam transfer 72,
and a cannula transfer 74. Cam 64 is a generally cylindrical
structure and is shown in detail in FIGS. 16A and 16B. A groove or
channel 65 is defined in the surface of cam 64. In one exemplary
embodiment, groove 65 is continuous and circumscribes the perimeter
of cam 64 but is not oriented perpendicularly to the longitudinal
axis of cam 64, i.e., groove 65 is angled with respect to the cam
axis. Opposing points on groove 65 such as points 65a and 65b
(FIGS. 2 and 3) define pairs of "apexes" that are spaced apart
along the longitudinal axis of the cam, i.e., the groove extends
along a portion of the length of the cam. Cam 64 also includes a
proximal opening 114 (FIG. 16a) for receiving a motor shaft and a
proximal recess 116 into which a shaft may be snugly received.
Holes 118 and 120 are provided for mounting position indicators
that cooperate with a position sensor to determine the angular
position of cam 64, and correspondingly, the linear position of
inner cannula 76 within the outer cannula lumen 110, as discussed
below.
[0048] Cam follower 68 is depicted in detail in FIG. 17B. Cam
follower 68 is a generally rectangular block shaped structure with
a hollow interior in which cam 64 is partially disposed. Cam
follower 68 also includes a hole 70 in its upper face in which a
ball bearing (not shown) is seated. The ball bearing rides in cam
groove 65 and engages cam transfer 72. As a result, when cam 64
rotates, cam follower 68 translates along the length of handpiece
42. Cam follower 68 also includes lateral slots 182a and 182b that
cooperatively engage corresponding members 178a, 178b from cam
transfer 72.
[0049] Cam follower 68 is disposed within a cam chamber 67 formed
in cam housing 69. Cam 64 is partially disposed in cam chamber 67
and extends proximally therefrom to engage motor 62. Cam housing 69
comprises part of distal portion 48 of handpiece 42. Cam 64 does
not reciprocate within cam chamber 67 and instead merely rotates
about its own longitudinal axis. However, cam follower 68
reciprocates within cam chamber 67 along the direction of the
length of handpiece 42. Cam follower 68 is open at its proximal end
to receive cam 64. As shown in FIGS. 15 and 16A, cam 64 may
optionally include a threaded distal end 123 that projects through
a distal opening 191 (FIG. 17b) in cam follower 68 and which
engages a nut 190 (FIG. 15) to prevent reciprocation of cam 64
relative to cam housing 69. Proximal cam bearing 186 and distal cam
bearing 188 (FIG. 15) may also be provided to support cam 64 as it
rotates within cam housing 69.
[0050] Cam transfer 72 extends from cam chamber 67 into a cam
transfer chamber 73 formed in upper housing 52. As best seen in
FIG. 17a, cam transfer 72 comprises a proximal end 72a that is
attachable to cam follower 68 and a distal end 72b that is
attachable to inner cannula 76 via cannula transfer 74. Proximal
end 72a comprises a pair of spaced apart, downwardly extending
members 178a and 178b, and distal end 72b comprises a pair of
spaced apart upwardly extending members 180a and 180b. Downwardly
extending members 178a and 178b are spaced apart in a direction
that is perpendicular to the length of cam 64 and handpiece 42,
while upwardly extending members 180a and 180b are spaced apart in
a direction that is parallel to the length of cam 64 and handpiece
42. Cam follower slots 182a and 182b engage downwardly extending
members 178a and 178b of cam transfer 72. Downwardly extending
members 178a and 178b of cam transfer 72 may be resilient and may
have engagement portions 179a and 179b on their free ends (e.g.,
hooks or clips) for securely engaging the bottom and side surfaces
of cam follower 68.
[0051] As best seen in FIG. 20, cannula transfer 74 comprises a
sleeve disposed about inner cannula 76. For ease of viewing, fluid
supply sleeve 302 is not shown in FIG. 20. Cannula transfer 74
comprises a proximal end 128, middle section 127, and distal end
126. Upwardly extending members 180a and 180b of cam transfer 72
define fork-shaped structures that receive and cradle middle
section 127 of cannula transfer 74. Distal end 126 and proximal end
128 of cannula transfer 74 are disposed outwardly of upwardly
extending members 180a and 180b and are shaped to prevent relative
translation between cam transfer 72 and cannula transfer 74. In the
depicted embodiments, distal end 126 and proximal end 128 of
cannula transfer 74 are enlarged relative to middle section 127 to
abut the upwardly extending, fork-shaped members 182a and 182b,
thereby preventing relative translation between cam transfer 72 and
cannula transfer 74. As a result, when cam transfer 72 reciprocates
along the length of handpiece 42, cannula transfer 74 reciprocates
as well. Because it is affixed to inner cannula 76, when cannula
transfer 74 reciprocates, it causes inner cannula 76 to reciprocate
within outer cannula 44.
[0052] In one exemplary arrangement, motor 62 is a brushed DC motor
and may be operably connected to cam 64 in a number of ways. In the
embodiment of FIGS. 2 and 3, motor 62 includes a distally extending
shaft 66 that extends into a proximal opening 114 and engages
recess 116 (FIGS. 16A and B) defined in cam 64. Shaft 66 may be
connected to cam 64 via a threaded connection, adhesive, or other
known connection means. In an alternate implementation, depicted in
FIG. 15, a separate cam coupler 184 is provided. Cam coupler 184 is
seated in proximal opening 114 and has a width greater than the
diameter of opening 114. Cam coupler 184 is also connected to motor
shaft 66 such that rotation of shaft 66 causes cam coupler 184 to
rotate, which in turn causes cam 64 to rotate therewith. One
revolution of motor shaft 66 causes cam 64 to rotate by one
revolution, which in turn causes inner cannula 76 to reciprocate by
one complete stroke, i.e., from the position of FIG. 2 to the
position of FIG. 3 and back to the position of FIG. 2.
[0053] Cam transfer 72 may be connected to cam follower 68 by
mechanical means, adhesive means or other known connection means.
In one exemplary embodiment, downwardly extending members 178a and
178b mechanically clip onto and removably engage cam follower 68.
In another embodiment, cam transfer 72 is adhesively affixed to cam
follower 68. In yet another embodiment, both mechanical and
adhesive connections are used. The ball bearing (not shown)
disposed in cam follower hole 70 traverses cam groove 65 as cam 64
rotates, causing cam follower 68 to reciprocate from the proximal
position of FIG. 2 to the distal position of FIG. 3. As a result,
cam transfer 72, cannula transfer 74 and inner cannula 76 translate
between their respective proximal positions of FIG. 2 and their
respective distal positions of FIG. 3 when motor 62 and cam 64
rotate.
[0054] Motor 62 is preferably selected to have a rotational speed
that allows inner cannula 76 to reciprocate from the position of
FIG. 2 to the position of FIG. 3 and back to the position of FIG. 2
at a rate of at least about 1,000 reciprocations/minute.
Reciprocation rates of at least about 1,200 reciprocations/minute
are more preferred, and reciprocation rates of at least about 1,500
reciprocations/minute are even more preferred. Reciprocation rates
of less than about 2,500 reciprocations/minute are preferred.
Reciprocation rates of less than about 2,000 are more preferred,
and reciprocation rates of less than about 1,800
reciprocations/minute are even more preferred. As best seen in FIG.
14, the rates of reciprocation of device 40 allow tissue to be
severed into "snippets" 112 which are relatively smaller than
"slug" tissue samples obtained by many prior devices. As the
reciprocation continues, a continuum of severed tissue snippets 112
is obtained.
[0055] As mentioned previously, outer cannula 44 includes an
opening 49 for receiving tissue into outer cannula lumen 110. As
best seen in FIGS. 8-12, opening 49 is preferably defined by a
cutting edge 51 that is configured to sever tissue and a
non-cutting edge 53 that is not configured to sever tissue. In
certain exemplary implementations, cutting edge 53 has a radial
depth "d" that is no greater than about 50% of the outer diameter
of outer cannula 44. In one exemplary implementation, cutting edge
51 is beveled in a radially inward direction, non-cutting edge 53
is not beveled, and cutting edge 51 is located immediately distally
of non-cutting edge 53. Inner cannula distal end 79 is preferably
configured to cut tissue. In one exemplary embodiment, distal end
79 is beveled in a radially inward direction around the
circumference of inner cannula 76 to provide a sharp edge. As
tissue is received in outer cannula opening 49, it is compressed
between inner cannula distal end 79 and outer cannula cutting edge
51, causing the received tissue to be severed from the surrounding
tissue.
[0056] Tissue cutting device 40 is particularly well suited for use
in cutting tough tissues such as spinal and brain tissues. Outer
cannula 44 and inner cannula 76 comprise materials that are
generally rigid, such as rigid plastics or metal. In one preferred
implementation, both cannulae comprise stainless steel, and more
preferably, 304SS typically used in medical grade instruments.
[0057] As best seen in FIGS. 9-14, to facilitate the cutting of
tough tissues, inner cannula 76 includes a hinge 80. For ease of
viewing, fluid supply sleeve 302 is not shown in FIGS. 9-14. Hinge
80 is located between inner cannula body section 81 which is
located on the proximal side of hinge 80 and inner cannula cutting
section 83 which is located on the distal side of hinge 80. In one
exemplary arrangement, hinge 80 is a living hinge. As used herein,
the term "living hinge" refers to a thin, flexible hinge that joins
two relatively more rigid parts together. In one example, hinge 80
is a living hinge that is integrally formed with inner cannula body
section 81 and inner cannula cutting section 83 by removing a
portion of the circumference of the inner cannula 76 along a length
L (FIG. 11). Hinge 80 allows cutting section 83 to pivot about
hinge 80 as inner cannula 76 reciprocates within outer cannula 44.
As inner cannula 76 translates in the distal direction, it contacts
tissue received in outer cannula opening 49 and encounters
progressively increasing resistance from the tissue as the tissue
is urged in the distal direction. As the resisting force of the
tissue increases, cutting section 83 pivots progressively more
until a zero annular clearance is obtained between inner cannula
distal end 79 and outer cannula opening 49. The received tissue is
severed and aspirated in the proximal direction along inner cannula
lumen 78 and received in tissue collector 58. Thus, inner cannula
lumen 78 provides an aspiration path from the inner cannula distal
end 79 to the inner cannula proximal end 77. Hinge 80 allows a
generally zero annular clearance to be obtained between inner
cannula distal end 79 and outer cannula opening 49 at cutting
section 83 while not affecting the annular clearance between inner
cannula body section 81 and outer cannula 44. This configuration
maximizes tissue cutting while minimizing frictional losses that
would otherwise occur due to the frictional engagement of the outer
surface of inner cannula body section 81 and the inner surface of
outer cannula 44 if a very small annular clearance between the
outer cannula 44 and inner cannula 76 were present.
[0058] Outer cannula opening 49 may have a number of shapes. In
certain examples, when outer cannula opening 49 is viewed in plan,
it has a shape that is generally square, rectangular, trapezoidal,
ovular, or in the shape of the letter "D." In certain other
exemplary implementations, outer cannula opening 49 is configured
to direct tissue so that it may be compressed as inner cannula 76
translates in the distal direction. In one exemplary embodiment,
depicted in FIGS. 10 and 12, outer cannula opening 49 has a
generally triangular shape when outer cannula opening 49 is viewed
in plan. As FIGS. 10 and 12 indicate, when viewed in plan, the
width of opening 49 in a direction transverse to the outer cannula
longitudinal axis varies longitudinally along the length of outer
cannula 44, and preferably narrows from the proximal to distal
portions of opening 49. When viewed in side elevation, cutting edge
51 slopes in a radially outward direction moving distally along
edge 51. As a result, as a tissue sample is distally urged within
outer cannula opening 49 by the action of inner cannula 76, the
tissue is increasingly compressed in the direction of the
circumference of inner cannula 76 (or in the direction of the
"width" of opening 49 when viewed in plan). To ensure complete
cutting, inner cannula distal end 79 preferably travels to a
position that is distal of outer cannula opening 49 during a tissue
cutting operation, i.e., there is an inner cannula overstroke.
[0059] As mentioned above, tissue cutting device 40 aspirates
tissue samples received in inner cannula lumen 78 to cause the
tissue samples to move in the proximal direction along the length
of the inner cannula 76. In certain methods of use, device 40 is
used to resect tissue without collecting tissue samples for further
analysis. In such embodiments, a tissue collector need not be
provided. In other embodiments wherein tissue collection is
desired, device 40 preferably includes a tissue collector 58 into
which aspirated tissue samples are deposited during a tissue
cutting procedure. Tissue collector 58 may be located remotely from
handpiece 42 and outside the sterile field during a tissue cutting
operation as shown in FIG. 21A. However, in an alternative
embodiment, as best seen in the examples of FIGS. 1-7, tissue
collector 58 is removably connected to handpiece 42. In either
embodiment, a fluid collection canister 192 is preferably located
between tissue collector 58 and a source of vacuum (such as vacuum
generator 153 in FIG. 21A) to protect the vacuum generating
apparatus from becoming contaminated or damaged by aspirated
fluids. In those embodiments that lack a tissue collector, fluid
collection canister 192 may be provided to collect both aspirated
fluid and tissue.
[0060] Referring to FIGS. 4-7, tissue collector 58 is connected to
upper housing 52 proximally of the inner cannula 76 to receive the
aspirated tissue samples. Tissue collector 58 is a generally
cylindrical, hollow body with an interior volume that is in fluid
communication with the inner cannula lumen 78 and a source of
vacuum (not shown in FIGS. 4-7). Tissue collector 58 is removably
secured to housing connector 96 to allow for the periodic removal
of collected tissue samples. Tissue collector 58 is preferably
secured to upper housing 52 in a manner that provides a
substantially leak-proof vacuum seal to maintain consistent
aspiration of severed tissue samples. A vacuum hose fitting 59 is
formed on the proximal end of tissue collector 58 and is in fluid
communication with the interior of tissue collector 58 and with a
vacuum generator, as will be discussed below.
[0061] In the embodiment of FIGS. 4-5, housing connector 96 is a
generally cylindrical, flange extending proximally from upper
housing 52. Upper shell 54 and lower shell 56 of upper housing 52
cooperatively define a cavity into which a seal holder 94 is
partially disposed. Seal holder 94 includes a distal annular recess
in which a seal 92, such as an o-ring, is disposed. Seal holder 94
also includes a central lumen through which inner cannula 76 is
slidably disposed. A proximally projecting portion 95 of seal
holder 94 projects away from upper housing 52 in the proximal
direction and is received within housing connector 96. As best seen
in FIGS. 2 and 3, inner cannula proximal end 77 preferably remains
within seal holder 94 as inner cannula 76 reciprocates during
operation of tissue cutting device 40. However, proximal end 77
moves within seal holder 94 as inner cannula 76 reciprocates. Seal
92 preferably comprises a resilient material such as an elastomeric
material. The sealing engagement of seal 92 and inner cannula 76
prevents air or fluids from leaking between inner cannula 76 and
upper housing 52 and aids in maintaining consistent aspiration of
samples through the inner cannula lumen 78.
[0062] Housing connector 96 includes connecting features 98 and 100
which are configured to engage with corresponding connecting
features 102 and 104 on tissue collector 58. In the embodiment of
FIGS. 4 and 5, connecting features 98 and 100 are "J" shaped slots
formed in housing connector 96, and connecting features 102 and 104
are complementary protrusions formed on tissue collector 58 which
engage connecting features 98 and 100, respectively. To connect
tissue collector 58 to housing connector 96, protrusions 102 and
104 are aligned with slots 98 and 100, and tissue collector 58 is
then inserted into housing connector 96 in the distal direction.
Tissue collector 58 is then rotated to fully engage protrusions 102
and 104 with slots 98 and 100. A seal 103 is provided around the
circumference of tissue collector 58 to sealingly engage the inner
surface of housing connector 96.
[0063] An alternate embodiment of tissue collector 58 is depicted
in FIGS. 6 and 7. In the embodiment of FIGS. 6 and 7, tissue
collector 58 is semi-elliptical in cross-section and includes a
hollow interior for receiving samples, as in the embodiment of
FIGS. 4 and 5. In the embodiment of FIGS. 6 and 7, a cylindrical
flange housing connector 96 is not provided. Instead, upper housing
52 is formed with an engagement recess 108 that engages a
complementary clip 106 formed on tissue collector 58. In each of
the foregoing embodiments, tissue collector 58 may be provided with
a filter (not shown) in its interior for collecting solid tissue
samples while allowing liquids and gases (e.g., air) to pass
through. Exemplary filters include medical grade mesh filters with
a mesh size smaller than that of tissue snippets 112.
[0064] In the embodiments of FIGS. 4-7, tissue collector 58
preferably has a longitudinal axis that is not collinear with the
longitudinal axes of handpiece 42, motor 62, or cam 64. The
longitudinal axis of tissue collector 58 is preferably
substantially coaxial with the longitudinal axis of inner cannula
76 to yield an "in-line" filter configuration. Tissue collector 58
and inner cannula 76 are both spaced apart from and substantially
parallel to the longitudinal axes of handpiece 42, motor 62, and
cam 64. Thus, the cutting axis (i.e., the outer cannula
longitudinal axis) and sample aspiration path axis are not coaxial
with the longitudinal axis of the handpiece 42. As a result, when
device 40 is used to cut tissue, the surgeon's view of the cutting
axis is not obstructed by his or her hand. In addition, the surgeon
can treat the proximal end of the filter as a "gun sight" and align
it with a tissue sample to be cut to thereby align the outer
cannula 44 with the tissue sample, providing enhanced ergonomic
benefits over previous devices, in particular, previous
neurosurgical devices. In the case of a device with a remote tissue
collector 58 such as the one depicted in FIGS. 21A and 21B, the
user can treat the proximal end of upper housing 52 as a gun sight
and align it with a target tissue.
[0065] When device 40 is used to cut tissue, outer cannula opening
49 must be aligned with the target tissue of interest to receive it
for cutting. The entire device 40 can be rotated about the
longitudinal axis of handpiece 42 to place outer cannula opening 49
at the desired location. However, this technique can be awkward and
may reduce the surgeon's dexterity. Thus, in an exemplary
embodiment, device 40 includes a selectively rotatable outer
cannula 44. As best seen in FIGS. 18-20, a rotation dial 60 is
provided and is rotatably seated in a cavity defined by upper shell
54 and lower shell 56 of upper housing 52. Rotation dial 60 is
configured such that when it is rotated, it causes outer cannula 44
to rotate about its longitudinal axis with respect to handpiece 42.
Rotation dial 60 is preferably connected to an outer cannula
connector portion 88. In the embodiment of FIGS. 18-20, outer
cannula connector portion 88 is a sleeve that is integrally formed
with rotation dial 60 and which is fixedly secured to outer cannula
44 such as by an adhesive or other known connection means. In the
exemplary embodiment of FIG. 20 rotation dial 60 has an outer
diameter that is greater than that of sleeve 88. For ease of
viewing, fluid supply sleeve 302 is not shown in FIG. 20.
[0066] As mentioned previously, inner cannula 76 includes a hinge
80 to allow inner cannula cutting section 83 to pivot toward outer
cannula opening 49 when device 40 is in operation. In order to
ensure the correct operation of hinge 80, the circumferential
alignment of hinge 80 and outer cannula opening 49 should be
maintained. Thus, rotation dial 60 is preferably connected to inner
cannula 76 such that when rotation dial 60 is rotated, both outer
cannula 44 and inner cannula 76 rotate in a fixed angular
orientation with respect to one another by an amount that directly
corresponds to the amount by which rotation dial 60 is rotated.
Rotation dial 60 may be directly connected to inner cannula 76 or
may use an intervening connecting device. However, rotation dial 60
should be configured to allow inner cannula 76 to reciprocate with
respect to rotation dial 60. As best seen in FIG. 20, rotation dial
inner cannula connector 86 may be provided to connect rotation dial
60 to inner cannula 76. Rotation dial inner cannula connector 86
comprises a proximal sleeve 87 disposed about inner cannula 76 and
a distal, radially extending annular flange 90 with an outer
diameter greater than that of the sleeve 87. Sleeve 87 and flange
90 may be in the shape of circular cylinders. Alternatively, and as
shown in FIGS. 18-19, sleeve 87 and flange 90 may be in the shape
of polygonal cylinders. Sleeve 87 is slidably received within the
annular cavity 130 at the distal end 126 of the cannula transfer 74
and keyed to the inner surface of cannula transfer 74 at annular
cavity 130 such that sleeve 87 can reciprocate with respect to
cannula transfer 74 while causing cannula transfer 74 to rotate
with sleeve 87 when rotation dial 60 is rotated. When inner cannula
76 is reciprocated, cannula transfer distal end 126 reciprocates
with respect to sleeve 87, thereby variably adjusting gap "G"
defined within annular cavity 130 (FIG. 20). Alternatively, cannula
transfer distal end 126 may be slidably received in an annular
cavity formed in sleeve 87 and may be keyed to the inner surface of
the annular cavity so that cannula transfer may reciprocate with
respect to sleeve 87 while still rotating with sleeve 87 when dial
60 is rotates.
[0067] As best seen in FIG. 20, rotation dial 60 includes a first
annular cavity 61 that is sized to receive and engage flange 90 in
a close fitting relationship. Rotation dial 60 may be press fit to
flange 90. In addition, adhesive connections or mechanical
connections may be used. Because rotation dial 60 is directly or
indirectly connected to both outer cannula 44 and inner cannula 76,
both cannulae rotate in direct correspondence to the rotation of
rotation dial 60, thereby allowing the user to adjust the
orientation of outer cannula opening 49 and inner cannula hinge 80
in a circumferential direction with respect to handpiece 42. As a
result, surgeons need not rotate the entire tissue cutting device
40 to obtain the desired angular orientation.
[0068] Rotation dial 60, outer cannula 44, and inner cannula 76 are
preferably configured for 360.degree. rotation. In addition,
tactile indicators are preferably provided on rotation dial 60 to
allow a user to reliably determine the extent to which dial 60 has
been rotated from a given starting point. The tactile indication
may comprise surface features defined on or in the exterior surface
of rotation dial 60. In one exemplary embodiment, depicted in FIGS.
18-20, a plurality of ridges 122 is provided around the
circumference of rotation dial 60 to provide tactile indication.
The ridges also act as grips and facilitate the surgeon's ability
to rotate the dial 60 without transferring unwanted motion to the
surgical site.
[0069] As mentioned previously, vacuum (sub-atmospheric pressure)
is applied to tissue collector 58 to aspirate severed tissue
samples through inner cannula 76 in the proximal direction. The
application of vacuum to inner cannula 76 via tissue collector
vacuum hose fitting 59 will have a propensity to produce a vacuum
at proximal end 45 of outer cannula 44 if leakage occurs between
inner cannula 76 and the components of upper housing 52. The
generation of a vacuum at outer cannula proximal end 45 will in
turn cause fluids and/or tissue samples at the distal end of outer
cannula 44 to flow into the annular clearance between inner cannula
76 and outer cannula 44 that extends from its proximal end at outer
cannula proximal end 45 to its distal end at inner cannula distal
end 79. This fluid and/or tissue can result in blockage of the
annular clearance and increased friction between the inner cannula
76 and outer cannula 44, resulting in degraded performance.
Accordingly, a seal 129 is preferably provided to prevent air
artifacts, fluid (water, saline, blood, etc.) flow, and tissue
sample flow in the annular clearance between inner cannula 76 and
outer cannula 44. The seal 129 is preferably disposed adjacent the
proximal end of the annular clearance between inner cannula 76 and
outer cannula 44, i.e., proximally adjacent to outer cannula
proximal end 45. As shown in FIG. 20, seal 129 is preferably
annular and circumscribes inner cannula 76, extending from the
outer surface of inner cannula 76 in a radially outward direction
as well as longitudinally along a portion of the length of inner
cannula 76.
[0070] In the embodiment of FIG. 20, rotation dial 60 and sleeve 87
act as a seal housing and include a seal cavity 131 which is an
annular cavity disposed immediately adjacent to and distal of first
annular cavity 61. Seal cavity 131 is sized to accept seal 129
therein. The seal 129 may be a conventional seal such as a solid,
flexible and/or elastomeric o-ring. However, seal 129 is preferably
amorphous and comprises a thixotropic material that is a
semi-solid. It is further preferred that seal 129 fill the entirety
of seal cavity 131 to ensure that cavity 131 is substantially leak
free. In the exemplary embodiment of FIG. 20, seal cavity 131 has
an outer diameter that is greater than the outer diameter of outer
cannula 44. Moreover, the annular thickness of seal cavity 131 is
preferably greater than the annular clearance between outer cannula
44 and inner cannula 76 to better ensure complete sealing of the
annular clearance.
[0071] In one exemplary embodiment, seal 129 is a grease--such as
the so-called "high vacuum greases"--that is formulated to
withstand vacuum conditions. Suitable high vacuum greases include
halogenated polymers. The halogenated polymers are preferably based
on cyclic ether or unsaturated hydrocarbon polymeric precursors. In
one exemplary embodiment, a perfluroropolyether (PFPE) grease is
used. Examples of such greases include the FOMBLIN.RTM. family of
greases supplied by Solvay Solexis, Inc. Other examples of such
greases include polytetrafluroroethylene greases ("PTFE") such as
TEFLON.RTM. greases supplied by DuPont. One suitable high vacuum
grease is FOMBLIN.RTM. Y VAC3 grease, which is a PFPE grease with a
PTFE thickener. The semi-solid seal 129 preferably has a kinematic
viscosity at 20.degree. C. of at least about 500 cSt, more
preferably at least about 800 cSt, and even more preferably at
least about 1200 cSt. Semi-solid seal 129 preferably has a
kinematic viscosity at 20.degree. C. of no greater than about 2500
cSt, more preferably no greater than about 2000 cSt, and even more
preferably no greater than about 1700 cSt.
[0072] The use of a semi-solid seal 129 has several advantages.
Because the seal is semi-solid, it will tend to absorb and dampen
vibrations transmitted from the reciprocation of the inner cannula,
thereby reducing overall vibration of device 40, and in particular,
the vibration transmitted to outer cannula 44. The dampening of
such vibrations is particularly beneficial because it reduces the
transmission of unwanted vibrations to outer cannula 44 which can
disturb delicate neurosurgical procedures. Moreover, because it is
not a solid seal, seal 129 will experience less heating and wear as
it is frictionally engaged by the reciprocating inner cannula 76.
In certain embodiments, a portion of seal 129 will adhere to the
outer surface of inner cannula 76 as it reciprocates producing a
zero slip velocity condition at the inner cannula 76 outer surface
which may further reduce frictional heating and degradation of seal
129. Because semi-solid seal 129 produces less frictional
resistance to the reciprocation of inner cannula 76 as compared to
conventional solid seals such as o-rings, it also decreases the
required motor power consumption and can facilitate the use of
lower torque and lower cost motors, which in turn facilitates
making device 40 disposable.
[0073] In one configuration, device 40 is connected to a vacuum
source and configured for variable aspiration, i.e., configured to
supply variable levels of vacuum to inner cannula lumen 78. As
depicted in FIG. 21A, in one exemplary implementation, a tissue
cutting system is provided which comprises tissue cutting device
40, a tissue collector 58, a controller 132, a vacuum generator
153, a vacuum actuator 144, a controllable valve 146, a vacuum line
151, and a fluid collection canister 192. As mentioned previously,
in FIG. 21A tissue collector 58 is located remotely from handpiece
42 and may be placed far enough from the handpiece 42 to remain
outside of the sterile field during a tissue cutting operation. As
best seen in FIG. 21B, tissue collector 58 is generally the same as
the tissue collector 58 depicted in FIGS. 4-5. Vacuum line 151a
connects the distal end of tissue collector 58 to proximally
projecting portion 95 of seal holder 94 on the proximal end of
tissue cutting device upper housing 52. In one arrangement, the
proximal end of vacuum line 151a includes a hose fitting 59b that
is integrally formed with a tissue collector coupler 296. Coupler
296 is similar in structure to tissue collector connector 96 (FIGS.
4-5) and is a cylindrical structure with a hollow interior for
receiving a portion of tissue collector 58. As best seen in FIG.
21B, tissue collector 58 includes projections 202 and 204 which
engage complementary slots 298 and 200 in coupler 296 in the same
manner that projections 102 and 104 engage slots 98 and 100 in
FIGS. 4-5. At the proximal end of tissue collector 58, hose fitting
59a engages vacuum line 151b which in turn is connected to fluid
collection canister 192. Fluid collection canister 192 is connected
to vacuum generator 153 via vacuum line 151c. Vacuum generator 153
is connected to controllable valve 146 by way of pressure line
147.
[0074] The outlet of tissue collection canister 192 is preferably
substantially liquid free and is connected to vacuum generator 153
via vacuum line 151c. Thus, vacuum generator 153 is in fluid
communication with tissue collector 58 and inner cannula lumen 78,
thereby generating a vacuum at the proximal end 77 of inner cannula
76 to aspirate severed tissue samples from inner cannula distal end
79 to tissue collector 58. The level of vacuum generated by vacuum
generator is preferably variable and selectively controllable by a
user. Maximum vacuum levels of at least about 0 in Hg. are
preferred, and maximum vacuum levels of at least about 1 in Hg. are
more preferred. Maximum vacuum levels of at least about 5 in Hg.
are even more preferred, and maximum vacuum levels of at least
about 10 in Hg. are still more preferred. Maximum vacuum levels of
at least about 20 in. Hg. are yet more preferred, and vacuum levels
of at least about 29 in. Hg. are most preferred.
[0075] The controllable valve 146 and the vacuum generator 153
provide a means for continuously adjusting and controlling the
level of vacuum applied to tissue collector 58 and the proximal end
of inner cannula lumen 78. Controllable valve 146 is supplied with
a pressurized gas, preferably air, or an inert gas such as
nitrogen. In one exemplary embodiment, the pressure applied to
controllable valve 146 is about 70 psi.
[0076] The system further includes an electrical controller 132
which receives and provides signals to the various components to
control or monitor their operations. Controller 132 provides
control signals to device 40 via motor drive control line 142 to
activate or deactivate motor 62. An aspiration valve control line
150 extends from the controller 132 to the controllable valve 146
which provides pressure to the vacuum generator 153. Signals to the
controllable valve 146 through line 150 are used to control the
amount of vacuum applied to tissue collector 58.
[0077] Controller 132 also receives electrical signals from the
various components of the system. For instance, a pressure
transducer 148 associated with the aspiration controllable valve
146, sends a signal along line 152 to the controller 132. The
signal is representative of the pressure supplied through
controllable valve 146 to vacuum generator 153. Thus, the
transducer 148 provides immediate feedback to the controller which
can in turn provide signals to aspiration controllable valve
146.
[0078] The user can adjust the system operating parameters by using
panel controls such as a console knob 138 and/or one or more
depressible controllers, such as a foot pedal 144. In one
embodiment, foot pedal 144 can be used to activate the motor 62 in
device 40, causing the inner cannula 76 to reciprocate within the
outer cannula 44. In another embodiment, foot pedal 144 can be used
to control the vacuum level supplied from vacuum generator 153 to
tissue collector 58 and inner cannula lumen 78. In yet another
embodiment, foot pedal 144 can be used both to activate motor 62
and to control the vacuum level supplied from vacuum generator 153
to tissue collector 58. In one arrangement, foot pedal 144 is
configured to variably increase the level of vacuum applied to
tissue collector 58 from a minimum level to a maximum level as foot
pedal 144 is depressed from a first position to a second position.
In such an arrangement, the first position is one in which foot
pedal 144 is not depressed all or is only slightly depressed, and
the second position is one in which foot pedal 144 is fully
depressed. In another embodiment, knob 138 is used to set a
preselected maximum vacuum level applied by vacuum generator 153.
Thus, by depressing foot pedal 144 from a first fully open position
to a second fully closed position, a plurality (preferably a
continuum) of vacuum levels can be supplied to tissue collector 58
with the maximum vacuum level being user adjustable via knob
138.
[0079] In one exemplary embodiment, foot pedal 144 includes two
switches (not shown) for providing variable vacuum and activating
motor 62. In another exemplary embodiment, once foot pedal 144 is
partially depressed from an open or undepressed position, motor 62
is activated. In accordance with the embodiment, continued
depression of foot pedal 144 activates vacuum generator 153. Foot
pedal 144 preferably provides continuous movement between a fully
open and a fully depressed position which in turn corresponds to a
plurality, and preferably a continuum, of vacuum levels that are
supplied to inner cannula lumen 78. Once foot pedal 144 is fully
depressed, the vacuum level supplied to inner cannula lumen 78
corresponds to a previously selected maximum vacuum level.
[0080] In certain illustrative examples, the user will adjust the
level of vacuum to achieve a desired level of "traction" in the
tissue surrounding the tissue to be severed. As used herein, the
term "traction" refers to the exertion of a pulling force on tissue
surrounding the target tissue to be severed. In some instances,
traction may be visualizable by the surgeon with the use of a
magnification instrument, such as a microscope or an endoscope. The
level of vacuum will also determine the amount of unsevered tissue
that is drawn into outer cannula opening 49, and therefore, the
size of the severed tissue snippets 112 (FIG. 14). Therefore, when
fine shaving operations are desired, the vacuum level will be a
relatively lower level than if debulking (large scale tissue
removal) is performed. Of course, the pre-selected maximum vacuum
level will also affect the maximum size of tissue that is drawn
into outer cannula opening 49, and therefore, will affect the
maximum size of severed tissue samples during any one operation.
Also, the vacuum level may be adjusted based on the elasticity,
fibrotic content, and hardness/softness of the tissue.
[0081] Console 134 may also include indicator lights 136, one of
which indicates the activation of cutting and one of which
indicates the activation of aspiration. Console 134 may further
include an analog display 140 with readouts for "aspiration" and
"cutter." The "aspiration" read out indicates the vacuum level
supplied to tissue collector 58 from vacuum generator 153. The
"cutter" read out indicates the speed of reciprocation of inner
cannula 76. In one embodiment, a speed sensor is mounted in device
40 to determine the speed of reciprocation of inner cannula 76 and
the sensor is input to controller 132.
[0082] As mentioned previously, when device 40 is used to perform a
cutting operation, inner cannula 76 reciprocates within outer
cannula opening 49 to sever tissue received within outer cannula
opening 49. When a cutting operation is complete, it may be
preferred to have inner cannula 76 come to rest at a position that
is proximal of the proximal edge 53 of outer cannula opening 49 to
ensure that tissue is not trapped between inner cannula distal end
79 and outer cannula cutting edge 51. However, in certain methods
of use, tissue cutting device 40 may be used as an aspiration wand
without cutting any tissue. In these embodiments, the stop position
of the inner cannula distal end 79 within outer cannula opening 49
determines the open area of the outer cannula 44, and therefore,
the aspiration levels that can be applied immediately adjacent
outer cannula opening 49. Thus, in some preferred embodiments, the
inner cannula stop position is user adjustable. Tissue cutting
device 40 may be used to aspirate a variety of fluids associated
with a neurosurgical procedure, including without limitation blood,
saline, cerebrospinal fluid, and lactated ringer's solution. In
certain examples, the inner cannula stop position is adjusted to
provide a desired degree of aspiration, outer cannula 44 is
positioned proximate a target tissue, and vacuum is applied to
manipulate the target tissue and draw it into outer cannula opening
49. Outer cannula 44 is then moved to a desired location or
orientation, thereby moving the target tissue to the desired
location or orientation. Once the target tissue has been
satisfactorily manipulated, a cutting operation is initiated. By
using device 40 in this manner, target tissues can be drawn away
from areas where tissue cutting operations are undesirable, and the
cutting can be performed remotely from those areas.
[0083] In one exemplary system, an inner cannula position control
is provided which controls the rest position of inner cannula 76
when motor 62 is deactivated. Referring to FIG. 24, cam rotational
position indicators 176a and 176b are mounted on the proximal end
of cam 64. In an exemplary embodiment, cam rotational position
indicators 176a and 176b are magnets having opposite poles. A
position sensor 174 is mounted on the inner surface of cam housing
69 and generates a signal indicative of the rotational position of
indicators 176a and 176b relative to position sensor 174. As
mentioned previously, the rotation of cam 64 correlates directly to
the position of inner cannula 76 within outer cannula 44. Thus, the
rotation of cam 64 can be sensed to indirectly determine the
position of inner cannula 76. Accordingly, indicators 176a/176b and
sensor 174 can be used to determine the position of inner cannula
76 with respect to proximal edge 53 of outer cannula opening 49
(FIGS. 10-12).
[0084] Referring to FIG. 22, an embodiment of a system for
controlling the operation of tissue cutting device 40 is provided.
The system includes a main control unit 158 ("MCU"), which (in the
embodiment shown) is configured as a microprocessor-based system.
In one implementation, MCU 158 is incorporated in controller 132
(FIG. 21A) and is operable to control the various operations of the
tissue cutting device 40. Foot switch 144 is electrically connected
to a number of inputs of MCU 158 via an equal number, K, of signal
paths 156, wherein K may be any integer. Panel controls, such as
knob 138, are electrically connected to a number of inputs of MCU
158 via an equal number, J, of signal paths 145, wherein J may be
any integer.
[0085] Display unit 140 is electrically connected to a number of
outputs of MCU 158 via an equal number, Q, of signal paths 141,
wherein Q may be any integer. In one exemplary implementation,
depicted in FIG. 21A, display unit 140 is provided on console
134.
[0086] As mentioned previously, tissue cutting device 40 includes
motor 62 coupled to the inner cannula 76 by an inner cannula drive
assembly 63. The motor 62 is electrically connected to motor
control unit 160 via a number, M, of signal paths 161 wherein M may
be any integer. The motor control unit 160 is, in turn, connected
to a number of outputs of MCU 158 via an equal number, N, of signal
paths 161. Cam rotational position sensor 174 is electrically
connected to a motor shaft position feedback input (SPF) of MCU 158
via signal path 162, and provides a motor stop identification
signal thereon as will be more fully described hereinafter. The
motor shaft stop identification signal provided by sensor 174 on
signal path 162 preferably provides MCU 158 with a motor stop
identification signal and may optionally provide a cutter speed
signal that is proportional to the motor speed for a geared system
or identical to the motor speed for a direct drive system.
[0087] Tissue cutting device 40 is further mechanically connected
to a vacuum unit 168 (e.g., a combination of controllable valve 146
and vacuum generator 153 in FIG. 21A) via conduit 163 (not shown in
FIG. 22), whereby the vacuum unit 168 provides a controllable
vacuum level to device 40 for aspirating tissue received in inner
cannula lumen 78. Vacuum unit 168 is electrically connected to a
vacuum control unit 166 via a number, P, of signal paths 169
wherein P may be any integer. The vacuum control unit 166 is, in
turn, connected to a number of outputs of MCU 158 via an equal
number, L, of signal paths 167, wherein L may be any integer. A
vacuum sensor 164, which may be a temperature compensated
solid-state pressure sensor, may be positioned within the conduit
151 and electrically connected to a vacuum feedback (VF) input of
MCU 158 via signal path 165. Alternatively, the vacuum sensor 164
may be disposed within hand piece 42 or within the vacuum unit 168
itself.
[0088] In operation, the MCU 158 is responsive to a vacuum command
signal, preferably provided by a corresponding control mechanism
associated with control panel 138, foot pedal 144, or an equivalent
control mechanism, to provide one or more corresponding vacuum
control signals to vacuum control unit 166 along signal paths 167.
The vacuum control unit 166, in turn, is responsive to the one or
more vacuum control signals to activate the vacuum unit 168 to
thereby provide tissue cutting device 40 with a desired level of
vacuum. The actual vacuum level provided to tissue cutting device
40 is sensed by vacuum sensor 164, which provides a corresponding
vacuum feedback signal to the vacuum feedback input VF of MCU 158.
The MCU 158 is then operable to compare the vacuum feedback signal
with the vacuum command signal and correspondingly adjust the one
or more vacuum control signals to achieve the desired vacuum level
within tissue cutting device 40. Such closed-loop feedback
techniques are well known in the control systems art.
[0089] In one alternative embodiment, the MCU 158 can be replaced
by individual microprocessors controlling the input and output for
controlling the operation of the motor 62 and the vacuum unit 168.
In this alternative embodiment, the motor control and vacuum
control microprocessors can be PIC16CXX Series microcontrollers
provided by Microchip, Inc. of Chandler Ariz. The motor control
microcontrollers can receive input signals from the motor driver
172 (FIG. 23) and position sensor 174, as well as the foot switch
144 and panel controls 138. Likewise, the vacuum microcontroller
can receive input signals from the vacuum sensor 164, the foot
switch 144 and panel controls 138. Each microcontroller can provide
its own output to its driven component and have its own display,
such as an LED display, indicative of its operational status.
Moreover, the two units can communicate with each other to ensure
clean cutting by proper timing of the cutting and aspiration
functions.
[0090] Referring now to FIG. 23, one exemplary embodiment of the
motor control unit 160 is shown in greater detail. The motor
control unit 160 in one embodiment includes a pulse width
modulation (PWM) generator circuit 170 having a motor speed input
connected to one of the MCU outputs 161.sub.1. If motor speed
control is provided, the output 161.sub.1 can provide a variable
voltage signal indicative of a desired motor speed and based upon
the position of a throttle, foot pedal, or other actuator. In
certain embodiments, an additional input is connected to another
one of the MCU outputs 161.sub.2. The signal at this output
161.sub.2 can be a motor slowdown signal as described below.
Alternatively, the output 161.sub.2 can constitute a braking signal
used in connection with a current feedback motor controller. As a
further alternative, the slowdown command may be communicated via
the motor speed command itself, rather than through a separate
signal 161.sub.2. In this instance, the output 161.sub.2 may not be
required.
[0091] In the illustrated embodiment, the PWM is disposed within
the motor control unit 160. Alternatively, the PWM can be
integrated into the MCU 158, or into the separate motor control
microprocessor discussed above. In embodiments that include motor
speed control, the motor speed input receives a motor speed signal
from MCU 158 indicative of desired operational speed of the motor
62. The slowdown input can receive a speed adjustment signal from
the MCU 158 based on an actual motor speed signal provided by a
motor sensor associated with the motor 62.
[0092] A motor driver circuit 172 is electrically connected to PWM
generator circuit 170 via signal path 173 and receives a PWM drive
signal therefrom, which is a pulse width modulated signal
indicative of desired motor speed. The motor driver circuit 172
provides a motor drive signal (MD) to motor 62 via signal path 175.
While the disclosed embodiment contemplates digital control of the
motor using the PWM generator circuit 170, alternative embodiments
can utilize closed loop feedback analog circuits, particularly
where slower cutting speeds are contemplated.
[0093] The motor drive signal includes a motor stop input that is
connected to another one of the MCU outputs 161.sub.1. In
accordance with an aspect of the present disclosure, MCU 158
provides a motor stop signal on signal path 161.sub.3, based on a
motor deactivation command provided by foot switch 144 or panel
control 138 and also based on a motor stop identification signal
provided by sensor 174, to stop the inner cannula 76 in a desired
position, as will be more fully described hereinafter. In certain
embodiments, only the motor stop signal is utilized to command the
motor to stop at the predetermined position. In these certain
embodiments, the motor slowdown signal on path 161.sub.2 can be
eliminated, or the input on path 161.sub.2 can be used for other
control signals to the motor control circuit.
[0094] As mentioned previously, when tissue cutting device 40 is
deactivated, inner cannula 76 may come to rest partially disposed
within outer cannula opening 49. Referring to FIGS. 25-27, three
different stop positions of inner cannula 76 are shown. For ease of
viewing, fluid supply sleeve 302 is not shown. FIG. 27 shows that
inner cannula 76 can be stopped in a position in which a portion of
the tissue T is trapped between the outer cannula opening 49 and
the inner cannula distal end 79. Efforts at withdrawing outer
cannula 44 from the surgical site may accordingly result in tearing
of the tissue portion T' away from the surrounding tissue base T.
Surgeons encountering such trapping would typically be required to
re-activate tissue cutting device 40 to release the tissue portion
T' from the surrounding tissue base T. To prevent such tissue
trapping from occurring, deactivation of the motor 62 is controlled
in such a manner that the inner cannula distal end 79 is positioned
remotely from the outer cannula opening 49 when inner cannula 76
stops reciprocating. However, in certain methods of use, device 40
is used as an aspiration wand. In those methods, the stop position
of inner cannula distal end 79 may be adjusted to different
locations within outer cannula opening 49 in order to adjust the
level of aspiration supplied to a region of the anatomy proximate
outer cannula opening 49. For example, stop positions may be
selected that limit the percent open area of outer cannula opening
49 to 25%, 50%, or 75% of the total area of opening 49.
[0095] Referring again to FIGS. 23 and 24, controlled deactivation
of the motor 62 will now be described in detail. When it is desired
to deactivate tissue cutting device 40, a motor stop command is
provided such as via foot switch 144 or a panel control 138. In one
embodiment, MCU 158 is responsive to the motor stop command to
provide a slowdown signal to the PWM generator via signal path
161.sub.2 which slows the action of motor 62. Preferably, the
slowdown signal corresponds to a predefined signal level operable
to drive the motor 62 at a motor speed below a motor speed
threshold level. Since motor 62 is a brushed DC motor, it has a
rotational resistance or resistive torque associated therewith as
described above. In addition, in some cases friction between the
inner cannula 76 and outer cannula 44 will increase the rotational
resistance. Due to this combined rotational resistance, operation
of the motor 62 will cease very rapidly or nearly instantly if the
motor drive signal on signal path 142 is disabled while driving
motor 62 below the motor speed threshold. Accordingly, when device
40 is used to cut tissue, alignment of position indicators 176a or
176b with sensor 174 preferably corresponds to a position of the
tissue cutting device 40 at which there is no danger of trapping
tissue between inner cannula distal end 79 and the outer cannula
opening 49, and sensor 174 is operable to produce the motor stop
identification signal when so aligned with indicator 176a or
176b.
[0096] In one embodiment, MCU 158 is operable to produce a motor
stop signal on signal path 161.sub.3 when sensor 174 detects
alignment of position indicators 176a or 176b therewith after one
passage thereby of indicator 176a or 176b since producing the
slowdown signal on signal path 161.sub.2. Allowing one passage of
indicator 176a or 176b by sensor 174 after issuing the slowdown
signal ensures that the rotational speed of motor 62 is at or below
the motor speed threshold when subsequently issuing the motor stop
command, regardless of the position of indicator 176a or 176b
relative to sensor 174 when the slowdown command was issued. After
one passage of indicator 176a or 176b by sensor 174 since issuing
the slowdown signal, MCU 158 is responsive to the signal provided
by sensor 174 indicative of alignment of indicator 176a or 176b
therewith, to produce the motor stop signal on signal path
161.sub.3. The motor driver 172 is responsive to the motor stop
signal to produce a motor disable signal on signal path 175. Due to
the inherent rotational resistance, motor 62 is responsive to the
motor disable signal to immediately cease operation thereof with
indicator 176a or 176b substantially aligned with sensor 174, and
with the inner cannula 76 accordingly positioned so as not to trap
tissue between inner cannula distal end 79 and the outer cannula
opening 44.
[0097] As mentioned above, in one exemplary embodiment, the inner
cannula stop position is user adjustable, such as by adjusting a
panel control 138 on console 134. In accordance with the
embodiment, it is contemplated that the stopped rotational position
of cam 64, and therefore the inner cannula distal end 79, may be
instead aligned with a predetermined differential distance between
the indicator 176a/176b and the sensor 174. The braking
characteristics of the inner cannula 76 and motor 62 can be
ascertained and the stopping distance determined so that this
predetermined differential distance can be calibrated accordingly.
However, in a preferred embodiment, when inner cannula 76 comes to
rest, the distal end 79 is located proximally of the outer cannula
opening 44 by a predetermined distance, as shown in FIG. 26.
[0098] A method of using device 40 to perform a tissue cutting
procedure will now be described in the context of a neurosurgical
procedure involving the cutting of a neurological target tissue. In
one example, the target tissue is brain tissue, and in another
example the target tissue is spinal tissue, for example, the tissue
of an intervertebral disk. In certain exemplary methods, the tissue
specimen being cut is a tumor or a lesion.
[0099] In accordance with the method, it is first determined
whether the cutting operation will be a debulking operation, a fine
shaving operation, or a cutting operation that is somewhere in
between a debulking and fine shaving operation. A surgical access
path is then created to the tissue sample of interest. In one
embodiment, the surgical path is created and/or the target tissue
is accessed using an "open" procedure in which the target tissue is
open to the atmosphere (e.g., a full open craniotomy). In another
embodiment, the surgical path is created and/or the target tissue
is accessed using a "closed" procedure in which the target tissue
is sealed from the atmosphere.
[0100] At this point, the distal end 79 of inner cannula 76 is
located proximally of outer cannula opening 49 due to the use of an
inner cannula stop position control of the type described
previously. The maximum vacuum level to be applied to device 40 is
then set using panel controls 138. Generally, higher vacuum levels
will be used for debulking procedures than for fine shaving
procedures as higher vacuum levels will tend to draw relatively
larger sections of tissue into outer cannula opening 49. In one
embodiment, the panel control 138 is a knob on console 134 that is
rotated to set the desired maximum vacuum level.
[0101] In one arrangement, device 40 is configured to be gripped
with a single hand during a tissue cutting procedure. Thus, the
surgeon will grasp handpiece 42 in the fingers of one hand and
insert outer cannula 44 to a location proximate the target tissue.
Depending on the hand and the surgeon's orientation with respect to
the target tissue, the surgeon may then rotate dial 60 to rotate
outer cannula 44 about its own longitudinal axis and orient outer
cannula opening 49 immediately adjacent the target tissue. The
rotation of outer cannula 44 with dial 60 causes inner cannula 76
to rotate such that a fixed rotational or angular relationship is
maintained between inner cannula 76 and outer cannula 44. Once the
opening is in the desired orientation, the motor 62 is activated,
for example, by beginning to depress pedal 144 from its fully
undepressed (open) position to a second partially depressed
position which causes motor control unit 160 to send a signal to
motor 62 on signal path 142. Motor 62 may also be activated by a
panel control 138. The rotation of motor 62 causes cam 64 to
rotate, resulting in the reciprocation of cam follower 68 and cam
transfer 72. The reciprocation of cam transfer 72 causes cannula
transfer 74 to reciprocate, thereby reciprocating inner cannula 76
within outer cannula lumen 110.
[0102] Once motor 62 is activated, vacuum is supplied to inner
cannula lumen 78. In one embodiment, as the pedal 144 is further
depressed (beyond the position at which motor 62 is activated),
vacuum generator 153 is activated. The surgeon then adjusts the
degree of depression of the foot pedal 144 to obtain the desired
level of vacuum by visualizing the movement of the target tissue
relative to the outer cannula opening 49. In certain embodiments,
the surgeon controls the vacuum level to obtain a desired amount of
traction in the tissue surrounding the target tissue. If the
surgeon desires to apply the previously set maximum vacuum level,
he or she depresses pedal 144 to its fully depressed position.
[0103] If desired, the surgeon may depress and partially release
the pedal 144 a number of times to manipulate the target tissue in
a satisfactory manner. Vacuum controller 166 is manipulable to
adjust the setpoint of vacuum generator 153 which is manipulable to
adjust the inner cannula vacuum level along a continuum of levels
below the pre-selected maximum level. In one embodiment, the extent
of depression of foot pedal 144 dictates the vacuum set point
supplied to vacuum control unit 166 on signal path 167, and
therefore, the amount of vacuum provided by vacuum unit 168. Vacuum
sensor 164 measures the vacuum supplied to tissue collector 58 and
feeds a signal back to main control unit 158 on signal path 165.
The measured vacuum is then compared to the set point applied to
vacuum control unit 166 via foot pedal 144, and the signal
transmitted to vacuum generator 153 is then adjusted to move the
measured vacuum value towards the set point. To obtain a vacuum
level equal to the maximum pre-set level, pedal 144 is completely
depressed. Maximum vacuum levels of at least about 0 in Hg. are
preferred, and maximum vacuum levels of at least about 1 in Hg. are
more preferred. Maximum vacuum levels of at least about 5 in Hg.
are even more preferred, and maximum vacuum levels of at least
about 10 in Hg. are still more preferred. Maximum vacuum levels of
at least about 20 in. Hg. are yet more preferred, and vacuum levels
of at least about 29 in. Hg. are most preferred.
[0104] Due to the resistance of the tissue drawn into outer cannula
opening 49, cutting section 83 pivots about hinge 80 and toward
outer cannula opening 49 as inner cannula 76 travels in the distal
direction. The inner cannula cutting section 83 continues to pivot
as it travels in the distal direction, eventually compressing
tissue within outer cannula opening 49 and severing it. The severed
tissue forms a continuum of tissue snippets 112 (FIG. 14) within
inner cannula lumen 78. Due to the vacuum applied to tissue
collector 58, snippets 112 are aspirated through inner cannula
lumen 78 in the proximal direction. They eventually exit inner
cannula lumen 78 at inner cannula proximal end 77 and enter tissue
collector 58 (or fluid collection canister 192 if no collector 58
is provided). Any fluids that are aspirated exit tissue collector
58 and are trapped in fluid collection canister 192. The surgeon
preferably severs tissue at a cutting rate of at least about 1,000
cuts/minute. Cutting rates of at least about 1,200 cuts/minute are
more preferred, and cutting rates of at least about 1,500
cuts/minute are even more preferred. Cutting rates of less than
about 2,500 cuts/minute are preferred. Cutting rates of less than
about 2,000 are more preferred, and cutting rates of less than
about 1,800 cuts/minute are even more preferred.
[0105] The surgeon may move device 40 around the target tissue
until the desired degree of cutting has been completed. Motor 62 is
then deactivated, for example, by completely releasing pedal 144 so
it returns to its fully undepressed (open) position. If an inner
cannula stop position control is provided, inner cannula 76
preferably comes to rest proximally of outer cannula opening 49, as
shown in FIG. 26. Outer cannula 44 is then removed from the
surgical site. Tissue collector 58 is then removed from upper
housing 52 of handpiece 42, and the collected tissue samples are
either discarded or saved for subsequent analysis. Fluids collected
in canister 192 are preferably discarded. If the remote tissue
collector of FIG. 21A is used, tissue samples may be removed from
it without removing outer cannula 44 from the surgical site or
otherwise disturbing the surrounding tissue.
[0106] As mentioned previously, tissue cutting device 40 includes a
fluid supply sleeve 302 which is selectively disposable about outer
cannula 44 (i.e., the user can install or remove fluid supply
sleeve 302 from outer cannula 44) to provide fluid to a surgical
site. As best seen in FIGS. 28-31, fluid supply sleeve 302 includes
an elongated channel section 304 that comprises an outer cannula
channel 314 and at least one fluid supply channel through which
fluids may pass. In the depicted embodiment, the at least one fluid
supply channel is fluid supply channel 312. When the fluid supply
sleeve 302 is in an uninstalled condition (e.g., FIG. 28), the
fluid supply channel 312 may be separated from the outer cannula
channel 314 along all or a portion of the length of elongated
channel section 304 by a barrier wall, membrane, etc. However, in
the example of FIG. 30, the outer cannula channel 314 is in fluid
communication with the fluid supply channel 312 along the entire
length of elongated channel section 304 when the fluid supply
sleeve 302 is in an uninstalled condition. As best seen in FIG. 30,
when fluid supply sleeve 302 is in an installed condition, outer
cannula 44 occupies outer cannula channel 314 and effectively
separates outer cannula channel 314 from fluid supply channel
312.
[0107] Referring to FIG. 1, hub 306 is connected to a fluid supply
line 308, which is preferably a length of flexible, plastic tubing.
Fluid supply line 308 includes a fluid source connector 310 on its
proximal end. Fluid source connector 310 may be any known type of
connector suitable for providing fluid flow. In the embodiment of
FIG. 1, fluid source connector 310 is a male luer fitting.
[0108] Hub 306 may be connected to elongated channel section 304 in
a variety of ways. One example is depicted in FIG. 29. As shown in
the figure, proximal end 317 of elongated channel section 304 is
connected to and disposed in the interior of hub 306. Hub 306
preferably includes a complementary channel (not separately shown)
in which proximal end 317 of elongated channel section 304 is
interfitted. The connection between elongated channel section 304
and hub 306 may be made in a variety of ways, including with
adhesives and mechanical fasteners. In addition, elongated channel
section 304 may be integrally formed with hub 306 such as by
integrally molding elongated channel section 304 and hub 306 as a
single piece. In the embodiment of FIG. 29, elongated channel
section 304 and hub 306 are separately formed and then connected
with an adhesive.
[0109] Hub 306 is generally cylindrical in shape. Hub 306 also
includes a proximal opening 322 and a distal opening 323. Outer
cannula 344 slidably projects through proximal end opening 322 and
distal end opening 323. However, at distal hub end opening 323,
outer cannula 44 projects through elongated channel section 304 of
fluid supply sleeve 302. As shown in FIG. 1, in one exemplary
configuration, the distal end 47 of outer cannula 44 projects
through and away from the distal end 320 of elongated channel
section 340 when fluid supply sleeve 302 is in an installed
condition on outer cannula 44. An interior channel (not separately
shown) is formed in the interior of hub 306 to retain outer cannula
44. Hub 306 may also include exterior surface features which
enhance the user's ability to grip the hub such as when fluid
supply sleeve 302 is being slid along outer cannula 44 to
reposition fluid supply sleeve 302 along the length of outer
cannula 44. In one example, a plurality of longitudinally oriented
grooves are spaced apart from one another around the circumference
of hub 306 and are provided to facilitate gripping. In another
example, a plurality of protruding axially oriented ridges are
provided and are spaced apart around the circumference of hub
306.
[0110] Fluid supply port 316 is provided along the length of hub
306 and is connected to fluid supply line 308. Fluid supply port
316 may comprise an opening in hub 306 and may also include a
projecting connector or flange for securing fluid supply line 308
therein. Interior fluid channel 318 is provided in hub 306 and is
in fluid communication with fluid supply port 316 and with fluid
supply channel 312 via open proximal end 319 in fluid supply
channel 312. Elongated channel section 304 includes a distal end
opening 313 in the fluid supply channel 312 through which fluid is
discharged to the surgical site, typically at or proximate to a
target tissue being resected.
[0111] Elongated channel section 304 is preferably rigid or
semi-rigid and made of a material that is suitable for use with
sterilization techniques, such as ethylene oxide sterilization,
Sterrad, autoclaving and gamma radiation sterilization. These
include resins and metals. One type of suitable polymer material is
heat shrinkable tubing. Additional suitable classes of polymers for
forming elongated channel section 304 include gamma-compatible
polyimides and polyamides, such as Kapton.RTM. polyimides supplied
by DuPont, and Nomex polyamides supplied by DuPont. Polyester and
polyethylene heat shrink tubing are also suitable classes of
polymer materials. One exemplary class of heat shrink tubing is
polyethylene terephthalate (PET) heat shrink tubing supplied by
Advanced Polymers, Inc. Suitable materials for forming hub 306
include stainless steel, aluminum, and polymeric materials such as
silicone polymers, and natural or synthetic rubbers.
[0112] As shown in FIG. 30, outer cannula channel 314 is
partially-cylindrical and defines a partially circular
cross-section. Fluid supply channel 312 may also be
partially-cylindrical. However, in the example of FIG. 30, fluid
supply channel 312 is generally in the shape of a partial elliptic
cylinder (i.e., a cylinder with a partial elliptical
cross-section). Inwardly directed ridges 324 and 326 define a
transition between outer cannula channel 314 and fluid supply
channel 312 along the length of fluid supply sleeve 302.
[0113] As mentioned previously, in one example, elongated channel
section 304 is formed from heat shrink tubing. In certain
embodiments, the heat shrink tubing is provided as a cylindrical
length of tubing and is then modified to provide a dual channel
structure such as the one depicted in FIG. 30. The dual channel
structure may be provided by disposing the cylindrical heat shrink
tubing around a mandrel having the cross-section of elongated
channel section 304 which is depicted in FIG. 30 and applying heat
to shrink the cylindrical tubing and conform its cross-section to
that of FIG. 30.
[0114] In one preferred example, when fluid supply sleeve 302 is in
an installed condition on outer cannula 44, outer cannula 44 may be
rotated with respect to fluid supply sleeve 302. In one
illustrative example, the surgeon may grip hub 306 with the fingers
of one hand to restrain its rotational movement and rotate outer
cannula rotation dial 60 with the thumb and/or fingers of the other
hand to adjust the circumferential position of outer cannula
opening 49. While fluid supply sleeve 302 may be configured to
rotate with outer cannula 44, in many instances it is preferable to
maintain the circumferential orientation of fluid supply sleeve 302
in order to prevent fluid supply line 308 from twisting. As shown
in FIG. 1, in one preferred orientation, fluid supply sleeve 302 is
circumferentially oriented such that fluid supply channel 312 is
disposed between the longitudinal axis L.sub.1 of handpiece lower
housing 50 and outer cannula channel 314 in a direction that is
substantially perpendicular to handpiece lower housing longitudinal
axis L.sub.1. In one example, wherein fluid supply sleeve 302 is
used to deliver a hemostatic agent, it is preferable to orient
fluid supply channel 312 such that it is spaced apart from outer
cannula opening 49 in a direction perpendicular to the lower
housing longitudinal axis L.sub.1 (see FIG. 31) to prevent the
aspiration of the hemostatic agent through outer cannula opening
49. However, other fluid supply channel 312 orientations may be
used depending on the procedure involved.
[0115] Fluid supply sleeve 302 may be connected to a fluid source
via fluid supply connector 310. The fluid source may be pressurized
or unpressurized. Unpressurized fluids may be elevated to provide
the necessary hydrostatic head to deliver the fluids through fluid
supply channel 312.
[0116] A variety of different fluids may be delivered to a target
tissue or proximate to the target tissue. In one example, irrigants
such as saline are used to hydrate tissue at the surgical site.
Saline may also function as a hemostatic agent to initiate a
"clotting cascade" which ultimately leads to the clotting of
ruptured blood vessels in tumors or other tissues at the surgical
site. Other hemostatic agents, sealants, and/or tissue adhesives
may also be delivered to a surgical site via fluid supply channel
312. Examples include liquid embolic systems such as Neucrylate, a
cyanoacrylate monomer derivative supplied by Valor Medical.
Neurcrylate is delivered as a liquid and forms a spongy, solid
material upon contacting blood. Another example of a suitable
hemostatic agent is supplied by Medafor, Inc. under the name Arista
AH Absorbable Hemostat. Arista AH functions as a molecular filter
by separating serum from cellular constituents. It absorbs water
from the blood and forms a gel matrix that slows blood flow and
serves to enhance clotting.
[0117] Fibrin sealants may also be delivered to a surgical site via
fluid supply channel 312. One suitable hemostatic matrix sealant is
FloSeal.RTM., a fibrin sealant comprising human thrombin which is
supplied by Baxter Hyland Immuno. Another suitable sealant is
Tisseel, a VH Fibrin Sealant comprising human thrombin, human
fibrinogen, and bovine aprotinin. Certain sealants may comprise two
or more fluid components that are mixed at or near the site of
delivery. In such cases, the at least one fluid supply channel 312
preferably comprises two or more fluid supply channels that contain
the respective two or more fluid components which are mixed at open
distal end 313 of fluid supply channel 312. For fluids that are
viscous and/or or gel-like in nature, a source of pressure such as
a pump is preferably provided to delivery them through fluid supply
channel 312 to the tissue.
[0118] Synthetic sealing agents may also be delivered via fluid
supply channel 312. One such example is CoSeal, a hydrogel
comprising 2 polyethylene glycol polymers supplied by Baxter. The 2
polymers are preferably delivered via two separate fluid delivery
channels and chemically bond to one another on mixing to form a
mechanical barrier that slows bleeding. Another suitable synthetic
seal is Duraseal, which is supplied by Confluent Surgical. Duraseal
comprises a polyethylene glycol polymer ester solution that is
mixed at the point of delivery with a trilysine amine solution.
Thus, fluid supply sleeve 302 is preferably provided with two fluid
delivery channels to facilitate mixing of the two solutions at the
point of delivery.
[0119] As mentioned above, in certain examples, it may be desirable
to include two or more fluid supply channels in fluid supply sleeve
302. However, the two or more fluid supply channels need not be
entirely separate along the length of sleeve 302. Instead, they may
combine to form a single channel mixing zone at a defined distance
from distal end opening 313. The length of such a mixing zone is
preferably selected to ensure thorough mixing without allowing the
fluids to form a solidified mixture prior to discharge from fluid
supply sleeve 302.
[0120] Tissue adhesive glues are another category of fluids that
may be delivered via fluid supply sleeve 302. Suitable tissue
adhesive glues include those formed from formaldehyde or
glutaraldehyde-based tissue adhesive glues. One suitable type of
glutaraldehye based tissue adhesive glue is BioGlue.RTM. a protein
hydrogel comprising bovine serum albumin, glutaraldehyde, and water
which is supplied by Cryolife, Inc. Depending on the viscosity of
the tissue adhesive glue, pressurized delivery may be required.
[0121] In certain examples, elongated channel section 304 is formed
with an imageable material to facilitate the identification of its
position within the patient. In one example, elongated channel
section 304 includes an MRI-imageable material. In another example,
elongated channel section 304 includes a positron emission
tomography (PET) imageable material such as a radioactive isotope.
Suitable isotopes include halogenated sugars such as
[.sup.18F]fluorodeoxyglucose and isotopes of amino acids such as
[.sup.11C]methionine. In one example, PET imaging is performed
while fluid supply sleeve 302 is inserted in the patient to locate
the position of fluid supply sleeve 302 (and outer cannula 44)
within the patient and relative to certain anatomical structures.
The radioactive isotope may be incorporated in the elongated
channel section 304 in a number of ways. In one example, the
radioactive isotope is added to a molten resin used to form
elongated channel section 304 and suspended within the solidified
resin. In another example, elongated channel section 304 is formed
with an inner and/or outer surface feature such as bores, holes,
cavities, or channels and dipped into a solution containing the
radioactive isotope. The isotope then wicks into the surface
feature. The surface feature could also comprise a "rough" surface
that defines a plurality of "valleys" in which the radioactive
material would remain. In addition, the surface feature may
comprise electrostatic charges to attract and hold the radioactive
material through electrostatic forces.
[0122] Fluid supply sleeve 302 can be used to deliver fluids when
tissue cutting device 40 is used in a tissue cutting mode or in an
aspiration wand mode. In one example, a tissue removal system
comprising tissue cutting device 40 with fluid supply sleeve 302
installed on the outer cannula 44 is provided. A fluid source is
provided and is connected to fluid source connector 310. A valve
may be provided between the fluid source and fluid source connector
310 to allow the surgeon to selectively deliver the fluid to fluid
supply sleeve 302. Alternatively, a valve may be provided between
fluid source connector 310 and hub 306.
[0123] The surgeon selectively positions fluid supply sleeve 302 at
a desired location along the length of outer cannula 44. In one
example, the surgeon grips hub 306 and advances or retracts fluid
supply sleeve 302 along outer cannula 44 to the desired location.
The outer cannula 44 is then inserted into the patient's body to a
location proximate the target tissue. In one example, fluid is
supplied from the fluid source through fluid supply line 308, into
hub 306, and through fluid supply channel 312. The fluid then exits
fluid supply sleeve 302 at fluid supply channel open proximal end
319 and contacts the target tissue and/or surrounding tissues
proximate the target tissue. A vacuum level may then be supplied to
inner cannula lumen 78 in the manner described previously. Motor 62
may be activated as described previously to cause inner cannula 76
to reciprocate within outer cannula lumen 110 and sever tissue
received in outer cannula opening 49. Fluid may be supplied via
fluid supply sleeve 302 before, during, and/or after reciprocation
of inner cannula 76 within outer cannula lumen 110. Severed tissue
snippets and/or fluids, including but not limited to the fluids
supplied via the fluid supply sleeve 302, are then aspirated
through inner cannula lumen 78 and into tissue collector 58 as
described previously.
[0124] In certain examples, tissue cutting device 40 may be used to
cut tissues with ruptured blood vessels which can cause significant
bleeding. One such example is a hemangioblastoma. In such cases, a
hemostatic agent or sealant of the type described previously may be
supplied during or after the tissue cutting procedure to minimize
blood flow.
[0125] In another exemplary method, a tissue cutting system
comprising tissue cutting device 40 and fluid supply sleeve 302 is
provided, and the system is used in an aspiration mode. In
accordance with the example, the surgeon selectively positions the
fluid supply sleeve 302 along the length of outer cannula 44 to
occlude a portion of outer cannula opening 49 as best seen in FIGS.
31 and 32. The fluid supply sleeve 302 may be used to occlude a
desired percent of the open area of outer cannula opening 49 and
therefore to selectively adjust the aspiration provided at outer
cannula opening for a given vacuum level supplied to inner cannula
lumen 78. For example, fluid supply sleeve 302 positions may be
selected that limit the percent open area of outer cannula opening
49 to 25%, 50%, or 75% of the total area of opening 49. A vacuum
level may then be supplied to inner cannula lumen 78 and may draw
surrounding tissues into the partially-occluded outer cannula
opening 49. In addition, fluids may be aspirated through outer
cannula opening 49, inner cannula lumen 78, tissue collector 58,
and collected in fluid collection canister 192 (FIG. 21A). With
tissue drawn into outer cannula opening 49, motor 62 may be
activated to sever the received tissue and collect it as described
previously. Thus, fluid supply sleeve 302 effectively allows the
surgeon to manually adjust the degree of aspiration at outer
cannula opening 49, and correspondingly, the size of the tissue
samples that are received in outer cannula opening 49 and severed
by inner cannula 76. Fluid may be supplied at or near the target
tissue via fluid supply channel 312 before, during, and/or after
tissue resection. However, fluid supply sleeve 302 may also be used
to adjust the degree of aspiration provided by tissue cutting
device 40 without supplying fluids.
[0126] It will be appreciated that the tissue cutting devices and
methods described herein have broad applications. The foregoing
embodiments were chosen and described in order to illustrate
principles of the methods and apparatuses as well as some practical
applications. The preceding description enables others skilled in
the art to utilize methods and apparatuses in various embodiments
and with various modifications as are suited to the particular use
contemplated. In accordance with the provisions of the patent
statutes, the principles and modes of operation of this invention
have been explained and illustrated in exemplary embodiments.
[0127] It is intended that the scope of the present methods and
apparatuses be defined by the following claims. However, it must be
understood that this invention may be practiced otherwise than is
specifically explained and illustrated without departing from its
spirit or scope. It should be understood by those skilled in the
art that various alternatives to the embodiments described herein
may be employed in practicing the claims without departing from the
spirit and scope as defined in the following claims. The scope of
the invention should be determined, not with reference to the above
description, but should instead be determined with reference to the
appended claims, along with the full scope of equivalents to which
such claims are entitled. It is anticipated and intended that
future developments will occur in the arts discussed herein, and
that the disclosed systems and methods will be incorporated into
such future examples. Furthermore, all terms used in the claims are
intended to be given their broadest reasonable constructions and
their ordinary meanings as understood by those skilled in the art
unless an explicit indication to the contrary is made herein. In
particular, use of the singular articles such as "a," "the,"
"said," etc. should be read to recite one or more of the indicated
elements unless a claim recites an explicit limitation to the
contrary. It is intended that the following claims define the scope
of the invention and that the method and apparatus within the scope
of these claims and their equivalents be covered thereby. In sum,
it should be understood that the invention is capable of
modification and variation and is limited only by the following
claims.
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